The present invention relates to a shield plate mounting apparatus for mounting a shield plate onto a casing of equipment, such as a recording/reproducing apparatus integrated with, for example, a television receiver, at a predetermined mounting angle.
FIG. 6 shows what is called a televideo, in which a television receiver 1 and a recording/reproducing apparatus 2, such as a magnetic tape unit and a DVD, are integrated with each other. To solve the problems that the recording/reproducing apparatus 2 is adversely affected by a magnetic field, which is generated by a magnetic source, such as a focusing coil 1a and a flyback transformer 1b of the television receiver 1, and that noises are caused on, for instance, a reproducing screen, a shield plate 4 is mounted on a casing 3 of the recording/reproducing apparatus 2.
Although screwing is an ordinarily conceivable means for mounting the shield plate 4, the number of components increases by that of necessary screws. Moreover, a screwing operation is time-consuming and troublesome. Furthermore, the manufacturing cost of the apparatus is high.
Thus, it is considered according to techniques described in, for instance, the Unexamined Japanese Utility Model No. Sho64-6406 that as illustrated in FIGS. 7A, 7B and 8, a steel top board portion 3a of the casing 3 is partly cut and raised so as to provide a plurality of (in this case, three) nearly-L-shaped projection portions 5 there in at predetermined angular intervals in such a manner as to protrude therefrom, and that as indicated by phantom lines in FIG. 7B, the shield plate 4 is elastically deformed and the circumferential portions thereof are engaged with the projection portions 5, respectively. Consequently, the shield plate 4 is fixed in such a way as to be unable to move in frontward, rearward, leftward, and rightward directions a to d and in an upward direction e and in a downward direction f.
Incidentally, in the case of an example illustrated in FIG. 7A, an opposite angle which a longitudinal axis A passing through the center O of the casing 3 forms with a longitudinal axis B passing through the center O of the shield plate 4, that is, a mounting angle xcex1 of the shield plate 4 is set at 30xc2x0 to thereby prevent the recording/reproducing apparatus from being adversely affected by a magnetic field that is generated by a magnetic source, such as the focusing coil 1a and the flyback transformer 1b. However, when the screen size of the television receiver 1 is changed to, for example, 14 inches or 25 inches measured diagonally, the positional relation between the magnetic source and the recording/reproducing apparatus 2 also changes. Thus, it is necessary to change the mounting angle xcex1 of the shield plate 4.
To meet the aforementioned requirement, a plurality of kinds of top board portions 3a, which differ in positions of the projection portion 5 from one another, are preliminarily prepared. Thus, the mounting angle xcex1 of the shield plate 4 is changed to 0 (see FIG. 9A) or 90xc2x0 (see FIG. 9B).
However, in the case of the television receiver of the aforementioned configuration, it is necessary to engage the circumferential portion of the shield plate 4 with each of the projection portions 5 of the top board portion 3a by elastically deforming and downwardly bending the shield plate 4 by a relatively large force. Such engagement is time-consuming and troublesome.
Further, it is necessary for changing the mounting angle xcex1 of the shield plate 4 to prepare a plurality of kinds of top board portions 3a, which are adapted to differ from one another in positions of the projection portions so that the top board portion 3a is changed to respond to the change in the mounting angle. Thus, the manufacturing cost of the apparatus is increased by the preparation of a plurality of kinds of top board portions 3a. 
In view of the drawbacks of the conventional apparatus, an object of the present invention is to provide a shield plate mounting apparatus enabled to reduce the manufacturing cost of a recording/reproducing apparatus by easily mounting a shield plate thereon at a desired mounting angle.
To achieve the fore going object, according to a first aspect of the invention, there is provided a shield plate mounting apparatus for mounting a shield plate on a casing of a recording/reproducing apparatus formed in such a way as to be integral with a television receiver, which comprises a plurality of projection portions provided on the casing at predetermined angular intervals in such a manner as to project therefrom, and a slip-off preventing piece formed in such a way as to be integral with a corresponding one of the projection portions and as to extend from the top end of each of the projection portions by being bent in a direction nearly perpendicular thereto. In this shield plate mounting apparatus, a plurality of mounting angles of the shield plate are set, and a plurality of through holes respectively facing the projection portions are pierced through the shield plate correspondingly to each of the mounting angles.
With such a configuration, predetermined through holes pierced through the shield plate are fitted onto the projection holes of the casing only by pushing the shield plate against the casing and causing the shield plate to slide during a state in which the shield plate is elastically deformed in a slightly upward direction.
Moreover, even in the case that change in the positional relation between the recording/reproducing apparatus and each of the magnetic sources, such as a focusing coil and a flyback transformer, is caused owing to change in the size of the television receiver, the mounting angle of the shield plate can suitably be changed in response to the change in the positional relation therebetween. This can reliably solve the drawback that the recording/reproducing apparatus is adversely affected, and that noises occur in a reproduced image.
Furthermore, there is no necessity for preparing a plurality of casings that differ from one another in positions of the projection portions, which are changed according to the change in the mounting angle of the shield plate, and that are prepared in the conventional apparatus. Thus, the cost of the apparatus can be reduced for that.
According to a second aspect of the invention, there is provided a shield plate mounting apparatus for mounting a shield plate on a casing of equipment, which comprises a plurality of projection portions provided on the casing at predetermined angular intervals in such a manner as to project therefrom and a slip-off preventing piece formed in such a way as to be integral with a corresponding one of the projection portions and as to extend from the top end of each of the projection portions by being bent in a direction nearly perpendicular thereto. In this shield, a plurality of through holes are pierced through the shield plate in such a fashion as to face the projection portions.
With this configuration, the through holes pierced through the shield plate are fitted onto the projection portions only by pushing the shield plate against the casing and causing the shield plate to slide during a state in which the shield plate is elastically deformed in a slightly upward direction. Thus, the shield plate can easily be mounted on the shield plate at a predetermined mounting angle.
According to a third aspect of the invention, in the second aspect of the invention, a plurality of mounting angles of the shield plate are set. Moreover, a plurality of through holes respectively facing the projection portions are pierced through the shield plate correspondingly to each of the mounting angles.
With this configuration, the shield plate can easily be mounted on the casing at a predetermined mounting angle only by fitting predetermined ones of the plurality of through holes, which are pierced through the shield plate, onto the projection portions. Moreover, there are no needs for preparing a plurality of casings that differ from one another in positions of the projection portions, which are changed according to the change in the mounting angle of the shield plate, and that are prepared in the conventional apparatus. Thus, the cost of the apparatus can be reduced for that.